How much drag does the rubber band cause, I bet you would get better run if it was consealed in a tube, plus the resistance of the water tension may also cause drag and a small loss of over all power. Cool I deal though.

You would probably be better off with a cancer engraver for that last. Back in the early 90's I was running mastercam and a cancer mill to make pcb slow and tedious, but it got the job done most of the time.

Im having a hell of a time getting a shave worthy edge on my chisel. I have honing stones some feel like a glass surface while others feel like the can scrape diamonds to dust. All my stones were left to me from my grandfather. They are mostly well used.